Conventionally, various ideas have been devised in order to increase a transmission capacity (hereinafter, may be referred to as “system capacity”) in a communication system. For example, in the 3rd generation partnership project long term evolution (3GPP LTE), discussions related to a technology to increase the system capacity using a “small cell” in addition to a “macro cell” have been held. Here, a “cell” is defined based on a “communication area” and a “channel frequency” of one base station apparatus (hereinafter, may be simply referred to as “base station”). The “communication area” may be the whole of an area where a radio wave transmitted from the base station reaches (hereinafter, may be referred to as “coverage area), or may be a divided area obtained by division of the coverage area (so-called, sector). The “channel frequency” is a unit of a frequency used by the base station for communication, and is defined based on a center frequency and a bandwidth. Further, the channel frequency is a part of an “operating band” allocated to the system as a whole. The “macro cell” is a cell of a base station capable of performing transmission with high transmission power, that is, a cell of a base station having a large coverage area. Further, the “small cell” is a cell of a base station that performs transmission with low transmission power, that is, a cell of a base station having a small coverage area.
That is, as a configuration of the communication system, a configuration in which cells having different sizes are mixed has been discussed as illustrated in FIG. 1. For example, as a configuration of the communication system, there may be a first configuration in which a plurality of small cells is included in a macro cell, a second configuration in which a plurality of small cells is arranged irrespective of a macro cell, and the like. FIG. 1 is a diagram illustrating a configuration example of a communication system.
Further, a communication terminal apparatus (hereinafter, may be simply referred to as “terminal”) performs processing of detecting a cell to be connected (that is, cell search processing) in order to start communication with a base station.
Conventional examples are described in 3GPP TSG-RAN Meeting#58, RP-122032, “New Study Item Proposal for Small Cell Enhancements for E-UTRA and E-UTRAN—Physical-layer Aspects,” December 2012, 3GPP TSG-RAN Meeting#58, RP-122033, “New Study Item Description: Small Cell enhancements for E-UTRA and E-UTRAN—Higher-layer aspects,” December 2012, Japanese Laid-open Patent Publication No. 2010-170469, and Japanese Laid-open Patent Publication No. 2000-253095
By the way, there is a need to extend the time for which the terminal can operate with single charging. However, there is a possibility that the power consumption of the terminal by cell search about a small cell is increased. That is, since a macro cell and a small cell basically use different frequency bands (inter-frequencies), the terminal performs the cell search processing of the macro cell and of the small cell separately. Under the circumstances where the position of the small cell is not known, there is a possibility that the cell search processing may be repeatedly executed at a position far from the small cell. In this case, the power of the terminal may be wastefully consumed.